Process for control of hydrocarbon reactions in moving solids contacting systems



July 3, 1951 D. D. MGKINNEY 2,558,769

PROCESS FOR CONTROL OF HYDROCARBON REACTIONS 1N MOVING SOLIDS CONTACTINCsYsTENs Filed Jan. 2, 1948 2 Sheets-Sheet 1 July 3, 1951 D. n. MGKINNEY2,558,769

PROCESS FOR CONTROL OF HYOROCARBON REACTIONS 1N MOVING SOLIDS CONTACTTNGSYSTEMS 2 Sheets-Sheet 2 Filed Jan. 2, 1948 Patented July 3, 1951 UNITEDSTATES PATENT OFFICE PROCESS FOR CONTROL OF HYDROCARBON REACTIONS INMOVING SOLIDS .5 Claims.

l This-'invention relates to improvements in processes wherein petroleumstocks and other hydrocarbons particularly high boiling hydrocarbonmaterials are contacted 'with solid cont-act materials in moving bedsystems.

A particularly successful process `in commercial use for the conversionof hydrocarbons, especially catalytic cracking, is characterized in thatthe hydrocarbons to be converted, which may be `in liquid, vapor ormixed phase, are contacted with a solid contact material in particulateform, especially in the form of small pellets or beads, which-is moving,a-s a non-turbulent bed, gravitationally downwardly through the reactor.The reactors Iare provided with distributing means which eiect'substantially even distribution of the entering stream of the catalystacross the reactor to provide the .upper surface-of a-catalyst bed.`Charge is admitted to the reactor vto loev applied to the bed indesired manner -at the top yor bottom of the bed. Catalyst and -crackedproduc-ts issue lseparately lfrom the reactor, whence the catalystpasses continuously `through a suitable regenerator wherein carbonaceousdeposit resulting `from the conversion reaction is Aburned off Vwith air.or other oxygen-containing gas and the temperature .of the catalyst israised.

'I'he present invention is concerned Awith improvements in processes vofthis type. In accordance with the invention the catalyst owing in'- tothereactor is in part introduced below the surface of the catalyst bedin the moving bed reactor. By proceeding in this way, more exact vandiexible .control over temperature and heat content of the catalyst bedis made possible. For example, the temperature differential across thclength of the bed is reduced, thus assuring a substantialreactionratethroughout the bed, whether the charge be in liquid, I vapor or mixedphase. Moreover, by this process the hydrocarbonsor at least a portionof them are vcontacted with catalyst at di'erent stages of catalyticdeactivation, which maybe due to the 'effect of the deposition of cokeor the action of impurities in the charge., whereby the higherconversion properties `of the less ,deactivated ycatalyst areadvantageously employed. Other Aadvantages of `the invention will ;beapparent .as `the description proceeds.

The inventionis especially valuable when rap.-

plied to -thevprocessing of heavy oils :such as crude.

bottoms, .distillation residues, and the like which are difficult, if:not impossible, to -vaporize .by the usual methodswithout.concomitantproductionl of coke and lower boiling thermally cracked 4prod-- ucts:including gasolinev Vin .substantial quantity.

CON-

2 Therefore the detailed description will largely be concerned withmethods of treating such oils. The invention has particular applicationto the catalytic cracking of such stocks when admitted tothe catalyst atleast partly in liquid phase.

In accordance with a preferred embodiment, the `invention vinvolvesintroducing a plurality of streams of clean catalyst at crackingtemperature within the reaction Zone. Heavy cracking stock at leastYpartly in the liquid phase and at temperatures below cracking level iscontacted 'with one .ofsaid streams before said stream reaches the mainbody of the catalyst within the reaction zone. Simultaneously at leastone and preferably a plurality of streams of the hot clean catalyst areseparately vintroduced `into Athe reaction zone and are added to crcommingled with the aforesaid rst stream but below the surface of thebed of catalyst.

'In practice ofthis embodiment Yof theinvention, vaporization andcracking ofthe charge rare initiated Iwith-in the portion `of catalystto which it Visl introduced. Thereafter, further heating and cracking ofany remaining liquid components of the charge, aswell as of vaporizedand any vapor phase components thereof, are effected in the main body ofcatalyst containing 'the additional stream or 'streams vof hot activecatalyst which is lfree or lrelatively `so of coke, tar, 4or otherdeposit resulting from contact -vaporization and conversion of 'theLheavy oil. v

Reference should be made'to the 'accompanying drawings for a more'complete description of l'the invention including preferred aspects andembodiments thereof.

'-I-nthe drawings:

`Fig. 1 is a vertical -sectional view partly in elevation showing avreaction zone Vhousing with associated elements r-in accordance withone embodiment of the invention;

Fig. r2 is `a sectional i-viewof -a portion of a reaction Zone housingvlin which vanother embodimentof 'the invention may -be practiced; yand,

`Fig.3'is -a'vertical sectional view partly in elevation showing anotherembodiment of this invention.

'With .reference vto Fig. il, lthere is shown a lreactor .fl inzwhich .acatalytic cracking reaction is carried out. A'The reactor is yprovidedywith'top =2 and .a conical Vbottom 'portion 3. Fresh catalyst, for`example from V9009-1000" fF., enters the -re actor a't desired rate:through lline 4 and establishes .a reservoir of fresh hot vcatalystwithin the .chamber Ldened `by plate t and top 2 lof the reactor. Liquidfeed .,:of the type referred to, xbelow cracking temperature, entersthrough line 's'. This liquid feed is distributed to a controlledportion of the contact mass through the distributor 8 which is shown asa nozzle but which may be any other suitable spray or atomizing devicewhich effects relatively uniform distribution of the atomized liquiddirectly to the surface of the main reactor bed or to a portion of freshcatalyst as it moves past the distributor, or which effects someappropriate distribution of the atomized liquid on the catalyst movingthrough or past the zone of spray and the catalyst comprising thesurface of the main reaction bed. A stream of fresh catalyst C isadmitted through a suitable opening 9 in plate 6 leading to pipe `I I.

. The vapor portion of the charge, if any, may be introduced to thesystem with the liquidl feed through line 1I, thus creating a mixedphase discharge through distributor 8, or it may be admitted separatelythrough line I2 or may be suitably divided in such fashion that some ofthe vapor charge may be admitted through line l and line I2. Productsare removed through line I3.

Fresh catalystI C after passing through opening 9 and pipe EI and overdistributing cone I4` is contacted with the atomized liquid oil chargefrom distributor 8 and thereafter continues to the surface of the mainreaction bed to assume Thereafter,

the position roughly shown as CI. the catalyst moves downwardly throughthe reactor. In order to introduce a portion of the hot catalyst C belowthe surface CI of the catalyst bed, there is provided a plurality ofpipes I6 leadingfrom openings I1 in plate 6. By this means freshcatalyst is transported from the upper fresh catalyst reservoir to aregion below the surface CI of the main bed of catalyst in such fashionthat fresh catalyst not previously contacted with either liquid or vaporcharge is admitted interiorly to the main bed of catalyst. This freshcatalyst after emerging from the pipes gravitates downwardly as a moreor less unitary mass designated as C2. K

With the usual type of vapor catalyst disengaging system channel membersI8 provide for the separation of the products from the spent catalystwhich thereafter passes through opening in tube sheets I9 and collectorpipes 2| withiinal discharge, at temperatures which may bek as much as100 F. below the inlet temperatures, from the system through line 22.The spent catalyst then passes through suitable reactivation treatment(not shown) whereby the inactivating carbonaceous deposit is removed byoxidation and an appreciable amount of the heat from the exothermicoxidative reaction is stored in the reactivated catalyst. Thisreactivated catalyst with its available heat is then returned to thereactor for reuse as hereinafter described.

When the operation is primarily one of cracking of heavy petroleumstocks, such charge stocks that boil predominantly or even substantiallycompletely above about 800 F. may be heated prior to admission to thecracking system to a suitable temperature such as about 40G-800 F. orhigher, as for example to about 700o i". Any suitable catalytic contactmass such` as activated clay catalysts, synthetic catalysts, mixtures ofclay and synthetic catalysts, or mixtures of active catalysts andrelatively inert heat capacity material having generally large dimeningcatalysts include naturally active or activated clays or earths such askaolins and montmorillonites; and synthetic plural oxide compositeseither siliceous or non-siliceous in character and containing forexample alumina, berryllia, zirconia or the like. These materials may bein the form of pellets, granules, chunks, beads or the like and havingthe above mentioned dimensions.

Petroleum charge stock having suitable temperature, as in the iange of40G-800 F., being in a suitable state of Vapor and liquid phase such asin a phase condition having approximately 'l0-90% more orless in thevapor phase and the remainder in the liquid phase, may be suppliedcontinuously through line l at superatmospheric pressure ranging forexample from 10-200 lbs. per square inch gage or otherwise as may berequired for charging the atomized hydrocarbon mixture to its intendeddestination. This hydrocarbon material after passage through line 'l isthen distributed through distributor 8 with relatively uni-` formdistribution of the desired type to the upper region of the catalystbed. The vaporized material may be comprised solely of vaporizedmaterial froinsuch heavy charge stocks as here-v inbefore designated ormay be comprised either entirely or partially of suitable extraneouscracking stock material, such as for example, light or heavy gas oilseither as fresh o1' recycle feed. Steam or other desirable gaseousmaterial such as hydrocarbon gases or vapors may be employedadvantageously and known manner in the preparation, delivery anddistribution of the hydrocarbon charge.

As hereinbefore stated, the oil-contacted catalytic material havingreached the surface of the main catalyst bed then proceeds downwardlythrough housing I. As this gravitational movement proceeds, it isdesirable that any liquid deposited on the catalyst be vaporized by theheat in the bed of catalyst. This heat, however, in many cases is notsufiicient to efect such vaporization either because of inequalities ofdistribution, ordeposition of excessive amounts of oil in relation tothe heat capacity of the catalyst, or other reasons including thegenerally en.

clothermic nature of the vaporization and of the cracking reaction. As aresult catalyst, or localized portions thereof, decreases in temperaturesometimes even to levers of low cracking and vaporizing efficiency. Thisinvention is especially advantageous because of the addition to thesystem of additional amounts of hot fresh catalyst which have not beenexposed to the liquid feed. The additional heat is transferred from thishot clean catalyst to the bed at portions of lthe latter requiringadditional heat, either by direct Contact of hot catalyst with therelatively cool catalyst or through the agency of the vapors circulatingthrough the catalyst bed.

Another advantage is inherent when at least an appreciable portion ofthe hot fresh catalyst is introduced into the main catalyst bed andclosely adjacent to the surface thereof when such introduction is moreor less directly under the liquid' feed inlet member. Under normaloperatingr conditions, the liquid feed is introduced under suchconditions that relatively uniform distribution of the liquid feedwithin the catalyst may be expected but abnormal conditions may arisewhereby the liquid iiow is affected, resulting in liquid dripping orrunning directly and in an undispersed condition to the surface of thecatalyst bed where, Without benefit of thisinventon 5. it would formconcentrations .offcoke and unprocessed oil. In provision of theconstantlyrenew ing hot clean catalyst in accordance with the inventionlosses of cracking efficiency that would otherwise result from suchconcentrations, when they occur, are minimized or even eliminated.

The amount of catalyst which is introduced to the system either fordirect contact with the liquid oil or as the fresh catalyst foradmission below the surface of the bed may vary considerably in respectto type of charge stock or operational requirements. For instance, itmay be desirable to admit a major portion such as 80% or more of thecatalyst for direct Contact with the hydrocarbon charge stock or it maybe desirable to admit the major portion of the catalyst such as up to80% below the surface of the bed. Under certain conditions it `may bedesirable to admit equal portions of the catalyst through both types ofadmission systems.

Considerable variations of form, type, volume and discharge positions ofthe transfer passage forming members through which the hot freshcatalyst is introduced intot he catalyst bed are possible. For instance,it may be desirable to have one or more of these members dischargingfresh catalyst centrally below the surface of the catalyst bed asindicated hereinbefore while other members at the same time and undersimilar conditions are dischargingr fresh catalyst below the surface ofthe bed to the perip-herial regions thereof. It is likewise possible toextend the discharge points of the members to any reasonable extentthroughout the length of the bed, such as ranging from a discharge pointdirectly below the surface of the bed to a point or points half-way ormore downwardly within the catalyst bed.

For a diagrammatic representation of another embodiment of apparatus inwhich this invention may be practiced, reference is made to Fig. 2 inwhich, under the same numerical designations of most of the elementsshown in Fig. 1, a section of a reactor is shown in which theconguration of the transfer passage forming pipes 24 results indischarge of the hot fresh catalyst within the bed at different levelsand positions. As shown, the catalyst admitted below the surface of thecatalyst bed through pipes 2d is distributed in part centrally to form acore of hot catalyst substantially directly under the liquid distributornozzle S, and in part is distributed at points more or less directlyunder the catalyst added to and forming the top surface of the bed tofurther aid in the distribution of catalyst within the reaction bed. Inaddition to the varying lateral points of discharge their verticalrelation is varied to increase the effect of the added contact materialwith its available heat and appreciable activity. An additional portionis admitted through openings 28 and lines 29 to establish and maintainthe bed level and upper surface.

Reference to Fig. 3 shows an embodiment of this invention in a reactorto which the hydro carbon charge is admitted substantially completely inthe vapor phase. In this figure hot fresh catalyst is admitted to thereactor 3S through pipe 3l and forms a reservoir of hot fresh catalyst CAwithin the chamber defined by plate 38 and top 39 of the reactor. Acontrolled portion such as 30 to 90% of the hot fresh catalyst C passesthrough certain of the openings il and thence through pipes 42 to formthe top section of the reaction bed Cl. Another controlled portion suchas '70 to 10% of the hot fresh catalyst C passes through others ofopenings 4I and thence through pipes i3 and discharges interiorly withinthe'catalyst bed as C2. 'Ihrottling cones 43a or similarly functioningdevices or means are positioned at the approximate upper level of thecontact mass portion shown as C2 in order that the rate of flow of thecontact mass portion Cl may be controlled to the desired extent byregulation of the cross-sectional area of the openings between cones 33ato substantially the same area as the discharge openings of pipes 132;The hydrocarbon feed vapor at temperatures, for example, of 750 to 950F. is introduced through line d4 and contacts and is partially convertedin the presence of catalyst Ci which is at least partially deactivatedby the deposition thereon of carbonaceous residue from the conversionreaction and/or components other than hydrocarbons which may be presentin the charge stock; thereafter the partially converted material inpassage through the reaction zone, is contacted with the hot freshcatalyst portion or portions C2 and is further converted with theassistance of the additional heat and catalyst of the portion orportions C2. It is obvious that the advantages will accrue in reactionsystems to which the hydrocarbon charge is admitted as vapor whether thedirection of vapor flow is as set forth in Fig. 3 or is admitted to flowin countercurrent relation with the movement of the catalyst bed.

The foregoing examples are not to be construed as the only means ofpracticing this invention since many modifications and variations can bepracticed Without departing from the spirit and scope thereof.Therefore, only such limitations as set forth in the appended claimsshould be considered.

I claim:

1. In a process for the conversion of heavy petroleum stocks which arecharged to a reaction zone in at least partially liquid phase, andwherein such conversion is effected in the presence of a bed ofgravitationally moving contact material, the improvement comprisingintroducing from a supply zone a first portion of clean contact materialat conversion conditions to a reaction zone to form the upper surface ofa gravitationally descending bed of such contact material in saidreaction zone, supplying heavy petroleum stock to the upper surface ofsaid bed by dispersing said vstock as a spray onto descending contactmaterial from a liquid distributing source above said bed, andintroducing a second portion of the clean contact material from saidsupply Zone at hydrocarbon conversion conditions into said descendingbed directly at a level below the upper surface of the bed and in atransversely limited area directly beneath the liquid distributingsource, thereby minimizing local concentrations of coke and unprocessedoil from liquid dripping in undispersed state upon the bed of contactmaterial from said liquid distributing source under possible abnormalconditions.

2. The process of claim 1 wherein at least part of the heavy petroleumstock sprayed onto said first portion of contact material is directed toengage such material prior to the formation of the upper surface of thebed by such contact material.

3. The process of claim 1 wherein the conversion conditions are crackingconditions and the contact material is cracking catalyst.

4. The process of claim l wherein the conversion conditions arevaporizing conditions and the 7 8 Contact material is substantiallyinert and of UNITED STATES PATENTS high heat capacity. Number Name Da e5. The process of claim 1 wherein the conver- 2 416 214 Payne Feb 1st1947 sion conditions are cracking conditions and the 2'429161 Hudson "MOct'- 14' 1947 contact material is a mixture of cracking catalyst 52'441170 Rose et May 11 1948 and relatively inert high heat capacitymaterial. 214901336 Crowley Dect 6 1949 REFERENCES CITED Y Commercial T.C. C. Operations on Partially l0 7 The following references are ofrecord in the glredvhageltoksbol g gggudrly file of this patent: page v

1. IN A PROCESS FOR THE CONVERSION OF HEAVY PETROLEUM STOCKS WHICH ARECHARGED TO A REACTION ZONE IN AT LEAST PARTIALLY LIQUID PHASE, ANDWHEREIN SUCH CONVERSION IS EFFECTED IN THE PRESENCE OF A BED OFGRAVITATIONALLY MOVING CONTACT MATERIAL, THE IMPROVEMENT COMPRISINGINTRODUCING FROM A SUPPLY ZONE A FIRST PORTION OF CLEAN CONTACT MATERIALAT CONVERSION CONDITIONS TO A REACTION ZONE TO FORM THE UPPER SURFACE OFA GRAVITATIONALLY DESCENDING BED OF SUCH CONTACT MATERIAL IN SAIDREACTION ZONE, SUPPLYING HEAVY PETROLEUM STOCK TO THE UPPER SURFACE OFSAID BED BY DISPERSING SAID STOCK AS A SPRAY ONTO DESCENDING CONTACTMATERIAL FROM A LIQUID DISTRIBUTING SOURCE ABOVE SAID BED, ANDINTRODUCING A SECOND PORTION OF THE CLEAN CONTACT MATERIAL FROM SAIDSUPPLY ZONE AT HYDROCARBON CONVERSION CONDITIONS INTO SAID DE-